1. Field of the Invention
The invention concerns a process for roller milling, hereafter referred to as rolling, of metal parts such as metal continuous sheets and/or shaped parts, which are guided during the rolling process through a gap formed between two work rollers.
2. Related Art of the Invention
The shaping process using roller profiling in place of deep drawing for the production of shaped parts is gaining increasing importance. For example, DE 198 07 830 A1 discloses a process for producing body and chassis components for vehicles of longitudinally seam-welded aluminum pipes or open rolled shapes. For this, a continuous sheet, usually referred to as a strip, is deformed in a continuous process first selectively over its width by means of rollers to a material thickness according to the required wall thickness. Thereafter the material is deformed by means of shaping rollers in a roller profiling assembly into a closed pipe shape or an open shape. In the case of a pipe shape, the side edges of the original planar semi-finished product are longitudinally welded with each other and subsequently the weld seam is deburred. The strip can in certain cases also be deformed locally over its length to various wall thicknesses by means of previously set up rollers. Thereby various wall thicknesses can be achieved not only over the circumference of the profile but rather also over the length of the profile, that is, in the axial direction. Thereby the wall thicknesses can be adapted over the length of the pipe or open profile to the most diverse locations of loads. Beyond this, a further material and weight savings is made possible.
From DE 199 39 166 A1 a process for flexible rolling of a metal strip is known, wherein the metal strip during the roller processing is led between a roller gap formed between two work rollers, and the roller gap during the roller processing is selectively moved, in order to achieve a varying of the strip thickness over the length of the metal strip. Thereby a good planar surface is achieved, namely even in the case of very broad metal strips. This is achieved thereby, that during each adjustment of the roller band or immediately thereafter, the bending lines of the work rollers are adjusted for achievement of a planar surface of the metal sheet depending upon the selected roller gap. This manufacturing process for production of a strip is laborious and expensive. Besides this, there occurs in this case a cross-section change only in the longitudinal direction of the roller sheet, and further, this is only suitable for sheets with low to average hardness.
In particular for light weight construction in the field of motor vehicles it is necessary to use sheets and shapes that are load-justified. This means that the construction component is to be produced or designed with the smallest possible wall thickness and is to be self-reinforced only in the particularly loaded or stressed areas. The self-reinforcement can therein be accomplished by a greater wall thicknesses or a particular structural design.
The invention is concerned with the task of providing a process for economical production of rolled sheets or shaped parts with local self-reinforcement areas, in particular for motor vehicle components.